60-GHz LTCC Antenna Arrays - Ultra-Wideband and 60 GHz Communications for Biomedical Applications - page 222

Fig. 22 Simulated radiation pattern for Element B at 60 GHz. a Port I: horizontal polarization,
b Port II: vertical polarization

The simulated radiation pattern at 60 GHz for Element B is shown in Fig. 22 .For
Port I, the 3-dB beamwidths are 110 and 90 ◦ in XoZ- and YoZ-plane, respectively.
The corresponding values for Port II are 80 and 120 ◦ . The back-lobe levels for both
the horizontal and vertical polarizations are about 18 dB. The simulated gain of

Element B are 5.3 dBi for Port I and 5.15 dBi for Port II at 60 GHz, respectively.

−

The Effect of the Open-Ended SICs on the Antenna Element

The proposed dual-polarized L-probe patch antenna element with the open-ended
SIC is shown in Fig. 23 . The distance between the power divider feeding network as
the Port I and the bottom metal ground of SL structure is h 2 . Whereas the distance
between the power divider feeding network as the Port II and the bottom metal ground
of SL structure is h 3 . The multilayer SL as the feeding network structure can be of
compact size and suppress the radiation from the feeding line. The open-ended SIC
structure is loaded around the L-probe feed dual-polarized antenna element. It is
composed of topped metal strip and metal vias fence constituted by a circle of vias.
The distance cd between the centers of two adjacent vias is 0.25 mm. The width
of the feed SL was chosen to be 0.1 mm, which corresponds to the characteristic
impedance of 50 . The detailed dimensions of the proposed dual-polarized antenna
element are shown in Table 2 .
The simulated S parameters of the antenna element with the open-ended SIC are
shown in Fig. 24 compared with the performances of the antenna element without the
open-ended SIC (Element B). For the antenna element with the open-ended SIC, as
the Fig. 24 a shown, the simulated impedance bandwidth is about 27.5 % with respect
to the center frequency of 63.25 GHz from 54.5 to 72 GHz for Port I (| S 11 | < −

10
dB) and about 32.2 % with respect to the center frequency of 63.75 GHz from 53.5